The South Bay Interchange is a massive interchange

Interchange (road)

In the field of road transport, an interchange is a road junction that typically uses grade separation, and one or more ramps, to permit traffic on at least one highway to pass through the junction without directly crossing any other traffic stream. It differs from a standard intersection, at which...

 in the South Bay

South Bay, Boston, Massachusetts

South Bay is a 10-acre site in Boston, Massachusetts sandwiched between Chinatown and the Leather District. It is roughly bounded by Kneeland Street, Hudson Street, the Massachusetts Turnpike mainline, and the Interstate 93 mainline. Currently owned by the Massachusetts Turnpike Authority , the...

 region of Boston, Massachusetts, USA. The interchange consists of Interstate 90

Interstate 90

Interstate 90 is the longest Interstate Highway in the United States at . It is the northernmost coast-to-coast interstate, and parallels US 20 for the most part. Its western terminus is in Seattle, at Edgar Martinez Drive S. near Safeco Field and CenturyLink Field, and its eastern terminus is in...

, the Mass Pike Extension

Massachusetts Turnpike

The Massachusetts Turnpike is the easternmost stretch of Interstate 90. The Turnpike begins at the western border of Massachusetts in West Stockbridge connecting with the Berkshire Connector portion of the New York State Thruway...

, and the Interstate 93

Interstate 93

Interstate 93 is an Interstate Highway in the New England section of the United States. Its southern terminus is in Canton, Massachusetts, in the Boston metropolitan area, at Interstate 95; its northern terminus is near St. Johnsbury, Vermont, at Interstate 91...

 concurrency

Concurrency (road)

A concurrency, overlap, or coincidence in a road network is an instance of one physical road bearing two or more different highway, motorway, or other route numbers...

 with US 1 and MA 3 south of the Thomas P. O'Neill Jr. Tunnel

Thomas P. O'Neill Jr. Tunnel

The Thomas P. "Tip" O'Neill, Jr. Tunnel is a highway tunnel built as part of the Big Dig in Boston, Massachusetts. It carries the Central Artery underneath downtown Boston, and is numbered as Interstate 93, U.S. Route 1, and Route 3. It roughly follows the route of the old elevated Central Artery,...

.

The interchange was constructed beginning in the late 1990s as a major feature of the Big Dig

Big Dig

The Central Artery/Tunnel Project , known unofficially as the Big Dig and as the Big Dug since completion, was a megaproject in Boston that rerouted the Central Artery , the chief highway through the heart of the city, into a 3.5-mile tunnel...

 project. By using a variety of methods including soil freezing and tunnel jacking to maintain adjacent subway

Massachusetts Bay Transportation Authority

The Massachusetts Bay Transportation Authority, often referred to as the MBTA or simply The T, is the public operator of most bus, subway, commuter rail and ferry systems in the greater Boston, Massachusetts, area. Officially a "body politic and corporate, and a political subdivision" of the...

, freight and commuter rail operations, engineers were able avoid major interruption of existing traffic flows. The name South Bay originates from the state of the area prior to nineteenth century land reclamation

Land reclamation

Land reclamation, usually known as reclamation, is the process to create new land from sea or riverbeds. The land reclaimed is known as reclamation ground or landfill.- Habitation :...

 efforts which filled an area of marshes and brackish water that was an estuary of Boston Harbor

Boston Harbor

Boston Harbor is a natural harbor and estuary of Massachusetts Bay, and is located adjacent to the city of Boston, Massachusetts. It is home to the Port of Boston, a major shipping facility in the northeast.-History:...

with dirt from nearby high ground.

External links

Design and Construction of Driven Pile Foundations: Lessons Learned on the Central Artery/Tunnel Project Federal Highway Administration